The present application claims priority to Japanese Application No. P10-234658 filed Aug. 20, 1998, which application is incorporated herein by reference to the extent permitted by law. The present application also claims priority to Japanese Application No. P11-180170 filed Jun. 25, 1999.
1. Field of the Invention
The present invention relates to a rotating drum assembly in which a magneto-resistive head is used as a read head, and a helical-scan magnetic recording/reproducing apparatus adopting the rotating drum assembly.
2. Description of Related Art
In magnetic recording/reproducing apparatuses such as a video tape recorder, audio tape recorder, computer data-storage system and the like using a magnetic tape as a recording medium, a helical-scanning system is adopted to provide an increased storage capacity by improving the recording density.
Such magnetic recording/reproducing apparatuses are required to have a higher recording density and storage capacity. To attain such high recording density and storage capacity, it has been proposed to use a magneto-resistive head (will be referred to as xe2x80x9cMR headxe2x80x9d hereinafter) as a read head in the helical-scan magnetic recording/reproducing apparatus.
The MR head uses a magneto-resistive element (will be referred to as xe2x80x9cMR elementxe2x80x9d hereinafter) to detect a magnetic field from a recording medium, and it is practically used as a read head of a hard disc drive. Generally, the MR head is more sensitive than the inductive head and provides a larger read output. Therefore, use of the MR head as a read head permits to attain a further higher recording density and storage capacity in practice.
The hard disc drive is adapted to read data with the MR head installed on a levitation slider and thus kept levitated on a magnetic disc. On the contrary, in a helical-scan magnetic recording/reproducing apparatus adopting the MR head as a read head, data is read from a magnetic tape with the MR head being slid on the magnetic tape.
However, the sliding of the MR head in contact on the magnetic tape can assure a large read output but leads to an abrasion of the MR head itself. When the MR head is abraded, the read output level varies and much noise takes place, which will cause read information signal to be deteriorated.
Especially an unused magnetic tape has a rougher surface that a used one. Therefore, when an unused magnetic tape is initially used, the MR head will be abraded very much due to the friction with the magnetic tape. Therefore, when designing the life of an MR head, much consideration should be given to how frequently the MR head is to be used with an unused magnetic tape. Eventually, the MR head cannot be designed to have a longer life.
Hence, a helical-scan magnetic recording/reproducing apparatus has not yet been developed which uses an MR head as a read head.
Accordingly, the present invention has an object to overcome the above-mentioned drawbacks of the prior art by providing a rotating drum assembly provided with an MR head as a read head, and a helical-scan magnetic recording/reproducing apparatus adopting the rotating drum assembly.
The above object can be attained by providing a rotating drum assembly comprising according to the present invention:
a cylindrical rotating drum;
a magneto-resistive head installed on the rotating drum to project at least a part thereof from the outer surface of the rotating drum; and
a tape-contact piece installed on the rotating drum so as to project from the outer surface of the rotating drum and to be in contact with the surface of a magnetic tape;
the tape-contact piece being formed to have a larger tape-contact width than that of the magneto-resistive head and disposed to be in earlier contact with the magnetic tape than the magneto-resistive head.
As mentioned above, the rotating drum assembly has the tape-contact piece formed to have the larger tape-contact width than the magneto-resistive head and disposed to be in earlier contact with a magnetic tape than the magneto-resistive head. The tape-contact piece smoothes the surface of the magnetic tape to prevent the magneto-resistive head from easily being abraded. The tape-contact piece may be a dummy head, inductive head or projection installed on the rotating drum to project from the outer surface of the rotating drum.
Also, in the rotating drum assembly according to the present invention, in case a dummy head is used as the tape-contact piece, the projection of the dummy head from the outer surface of the rotating drum should be larger than that of the magneto-resistive head from the outer surface of the rotating drum, whereby the pressure of contact between the magneto-resistive head and a magnetic tape can be smaller than that between the dummy head and magnetic tape to prevent the magneto-resistive head from easily being abraded.
Also, the above object can be attained by providing a helical-scan magnetic recording/reproducing apparatus comprising according to the present invention:
a cylindrical rotating drum;
a magneto-resistive head installed on the rotating drum to project at least a part thereof from the outer surface of the rotating drum; and
a tape-contact piece installed on the rotating drum so as to project from the outer surface of the rotating drum and to be in contact with the surface of a magnetic tape;
the tape-contact piece being formed to have a larger tape-contact width than that of the magneto-resistive head and disposed to be in earlier contact with the magnetic tape than the magneto-resistive head.
In the magnetic recording/reproducing apparatus according to the present invention, the rotating drum has installed thereon the tape-contact piece formed to have the larger tape-contact width than the magneto-resistive head and disposed to be in earlier contact with a magnetic tape than the magneto-resistive head. The tape-contact piece smoothes the surface of the magnetic tape to prevent the magneto-resistive head from easily being abraded. The tape-contact piece may be a dummy head, inductive head or projection installed on the rotating drum to project from the outer surface of the rotating drum.
Also, in the magnetic recording/reproducing apparatus according to the present invention, in case a dummy head is used as the tape-contact piece, the projection of the dummy head from the outer surface of the rotating drum should be larger than that of the magneto-resistive head from the outer surface of the rotating drum, whereby the pressure of contact between the magneto-resistive head and a magnetic tape can be smaller than that between the dummy head and magnetic tape to prevent the magneto-resistive head from easily being abraded.
These objects and other objects, features and advantages of the present intention will become more apparent from the following detailed description of the preferred embodiments of the present invention when taken in conjunction with the accompanying drawings.